Recent technological advances in modern Radio Access Technologies (RATs), such as Multiple Input Multiple Output (MIMO), the addition of new frequency bands, and multi-carrier schemes, have led to dramatic increases in data throughput capability. As a result, devices operating according to popular RATs such as WiFi (defined according to the IEEE 802.11 standard) and the telecommunications standards defined by the 3rd Generation Partnership Project (3GPP, including Global System for Mobile Communications (GSM), Universal Mobile Telecommunication Systems (UMTS), and Long Term Evolution (LTE)) must have transceiver components capable of supporting high speed data buses.
However, the incorporation of high speed data buses in transceiver devices may yield increases in unwanted electrical noise, which may in turn reduce the sensitivity of radio frequency (RF) receivers. The issue of increased noise may be conventionally addressed with passive noise reduction techniques, such as by providing isolation in the coupling path between the high speed data buses and all victim blocks. The required levels of isolation may be relatively high (e.g. 60 dB or greater), which may be difficult to guarantee in many transceiver components.
In addition to passive isolation techniques, active noise mitigation approaches such as spectral line coding (SLC) may be able to shape the frequency spectrum of bus data in order to reduce the effects of data bus noise in targeted RF bands. SLC implementations may encode data by selecting a stream of encoded symbols that reduces the spectral energy of noise in the targeted RF bands.
However, conventional SLC approaches may only be able to reduce noise energy in a single RF band. Accordingly, existing SLC techniques may not be able to cancel out noise in multiple RF bands in parallel. This may be especially problematic in Global Navigation Satellite System (GNSS) receivers including Global Position System (GPS), GLObal NAvigation Satellite System (GLONASS), Galileo, and Beidou, which are sensitive in multiple RF bands.
Furthermore, existing SLC techniques only address noise components that are directly related to the data on the bus, but do not address potentially dominant noise components arising from the common-mode signal of differential data lines that are related more directly to transitions in the bus data rather than to the data itself and other spectral components that are derived by non-linear functions out of the data signal. Accordingly, the dominant common-mode signal in a differential data line may be unaffected by the aforementioned existing SLC techniques, and accordingly may continue to contribute noise to victim blocks in a substantially unrestricted manner. As used herein, “data-dependent” refers to signal and noise components that are addressed by existing SLC techniques, and “transition-dependent” refers to signal and noise components more directly related to data transitions rather than to the data itself.